Conventional automotive or architectural glazing or window structures often include a laminate typically made of two rigid glass or plastic sheets and an interlayer of plasticized polyvinyl butyral (PVB). The glazing is prepared by first placing a PVB layer between the two rigid sheets. The PVB layer is typically sized and positioned so as to either extend beyond or be flush with the periphery of the two rigid sheets. Air is then eliminated from the engaging surfaces, and the assembly is then subjected to elevated temperature and pressure (e.g., in an autoclave) to fusion bond the PVB and the rigid sheets into a laminate suitable for use in the window structure. After the rigid sheets are bonded together, any excess PVB extending out beyond the periphery of the rigid sheets is typically trimmed off. Such laminates have been used for automotive and architectural glazing applications.
These laminates have also included a functional sheet engineered to enhance the performance of the resulting glazing. One such functional sheet is designed to reflect infrared radiation (IR) away from the interior of a building or vehicle cabin. An example of such an IR reflective sheet can be found in U.S. Pat. Nos. 5,882,774, 6,049,419, 5,103,337, 5,223,465, 5,360,659 and 4,799,745. In the forming of a laminate suitable for a glazing or window structure, such a functional sheet is typically bonded between two sheets of glass using two sheets of PVB, with one sheet of PVB being used to bond one of the glass sheets to each side of the functional sheet.